PCIe lanes on a Maximus V Extreme?

[rfkrocktk]

I'm about to get an SLI setup together and I'm somewhat concerned about my PCIe lane count. With the SLI setup, I'll have two graphics cards, one RAID card, and one Firewire card in my board.

The graphics cards will run (I assume) on 8 lanes each, though they both support x16. The RAID card uses PCIe 2.0 x8. The Firewire card is x1, I believe.

Will I even be able to run everything in this configuration or am I already out of PCIe lanes on my Maximus V Extreme (Z77)?

 

[MattNo5ss]

Yeah, you'll be able to run all those PCIe cards together.

 

[rfkrocktk]

How many PCIe lanes do I have? I guess I'm not really understanding the logic of how they work.

Will I be running the 2 VGAs and 1 RAID in x8 x8 x8? How will it map out?

 

[MattNo5ss]

You have 16 lanes native on the CPU, and 16 more provided by the PLX chip on the motherboard. So, 32 total.

You'll need to put the GPUs in the slots 1 and 2 and the remaining cards in slots 4-6. Slot 3 is disabled when using slots 4 or 6.

 

[rfkrocktk]

Ah, thanks for helping me figure that out. On X79, how many lanes do you usually get? Would it be possible on X79 to run two cards at x16? (Sample setup: Rampage IV Extreme, Intel 3930k)

 

[EarthDog]

The difference in performance between 8x/8x and 16x/16x is 1%. That said, I wouldnt jump up to that platform simply for that reason, no way. Thats a HUGE difference in money for 1% gains. Though, Im not sure if that will change with a higher resolution. I havent seen it tested.

Not to mention, you dont need that high end of a motherboard... nor close to it for your needs. You just need the slots which other, much cheaper boards have. 3930K has, I think 32 lanes native to the CPU.

 

[rfkrocktk]

That's good to know that x16 is mainly just marketing, I didn't know. Other forums seemed to make it a big deal that you'd quickly run out of PCIe lanes on X77.

 

[EarthDog]

You can... but as someone mentioned above, boards with a PLX chip make more on that platform (and X79 too).

 

[rfkrocktk]

Good to know, thanks